Other · Reduced-amide opioid peptidomimetic
TIPP-psi
Also known as TIPP[ψ]; H-Tyr-Tic-ψ[CH2NH]-Phe-Phe-OH
A reduced-amide TIPP analogue for examining δ-opioid receptor antagonism and the effects of peptide-backbone modification.
- Length
- 4 amino acid-derived residues
- Half-life
- Not well characterised
- Mechanism
- TIPP-psi is a high-affinity, δ-opioid receptor-preferring antagonist. Replacement of the Tic–Phe amide with a ψ[CH2NH] linkage changes backbone geometry and hydrogen-bonding properties, modifying receptor recognition relative to TIPP.
- Studied in
- Recombinant receptor assays, radioligand competition experiments and isolated tissue models examine its δ-opioid receptor antagonism and backbone-dependent selectivity.
About TIPP-psi
TIPP-psi belongs to the synthetic Tyr-Tic opioid peptide series developed through conformationally constrained ligand research. Its structure is H-Tyr-Tic-ψ[CH2NH]-Phe-Phe-OH: the conventional amide between residues two and three is replaced by a methyleneamine linkage. The psi notation identifies this specific backbone substitution rather than an additional amino acid. Removing the amide carbonyl changes local polarity, hydrogen bonding and conformational behaviour while retaining the four-residue framework.
Research characterises TIPP-psi primarily as a potent δ-opioid receptor antagonist, with selectivity evaluated against μ- and κ-opioid receptors. Functional assays can measure its ability to oppose agonist-dependent Gi/o signalling, while competition experiments assess receptor affinity independently. The reduced linkage is also relevant to studies of proteolytic susceptibility, although resistance at one bond does not establish overall biological persistence. Comparisons require matched receptor expression, incubation conditions and peptide integrity measurements.
Laboratory notes
- Verify that the reduced ψ[CH2NH] linkage is located between Tic and Phe; a generic TIPP identity statement is insufficient.
- Use an authenticated reference and suitable structural analysis where needed, since intact mass alone does not fully establish linkage position or stereochemistry.
- Measure stability in the actual assay matrix rather than assuming that the reduced bond prevents all peptide degradation.
Storage and reconstitution basics: storage guide.
Questions about TIPP-psi
What does the psi symbol mean?
It denotes a non-standard backbone linkage. In TIPP-psi, ψ[CH2NH] replaces the Tic–Phe carbonyl-containing amide with a methyleneamine group.
Is TIPP-psi an endogenous peptide?
No. It is a synthetic peptidomimetic designed for opioid-receptor structure–activity research.
Does the reduced linkage establish a longer half-life?
No. It may change susceptibility to particular peptidases, but overall persistence depends on the matrix, other cleavage sites and experimental conditions.
Is TIPP-psi for human use?
No. It is supplied strictly for in-vitro laboratory research and is not for human or animal consumption.
Related research peptides
All products are sold for laboratory research use only. Not for human consumption, not a medicine, not for diagnosing, treating or preventing any condition.